Standardize usage of virtual/override/final in content/browser/

content/browser/histogram_synchronizer.h

Index: content/browser/histogram_synchronizer.h
diff --git a/content/browser/histogram_synchronizer.h b/content/browser/histogram_synchronizer.h
index 4cfb766e52fe9380fc2011e02ba8029697885189..b7d75e03d45d70ec6ea1411b472133a9077cc62a 100644
--- a/content/browser/histogram_synchronizer.h
+++ b/content/browser/histogram_synchronizer.h
@@ -80,7 +80,7 @@ class HistogramSynchronizer : public HistogramSubscriber {
   class RequestContext;
 
   HistogramSynchronizer();
-  virtual ~HistogramSynchronizer();
+  ~HistogramSynchronizer() override;
 
   // Establish a new sequence number, and use it to notify all processes
   // (renderers, plugins, GPU, etc) of the need to supply, to the browser,
@@ -95,14 +95,14 @@ class HistogramSynchronizer : public HistogramSubscriber {
 
   // Update the number of pending processes for the given |sequence_number|.
   // This is called on UI thread.
-  virtual void OnPendingProcesses(int sequence_number,
-                                  int pending_processes,
-                                  bool end) override;
+  void OnPendingProcesses(int sequence_number,
+                          int pending_processes,
+                          bool end) override;
 
   // Send histogram_data back to caller and also record that we are waiting
   // for one less histogram data from child process for the given sequence
   // number. This method is accessible on UI thread.
-  virtual void OnHistogramDataCollected(
+  void OnHistogramDataCollected(
       int sequence_number,
       const std::vector<std::string>& pickled_histograms) override;